Infrared detectors have long been used in thermal imagers for viewing at night, or for viewing through clouds, smoke and dust. A conventional infrared imager has an array of large-area detectors wherein each detector corresponds to a single picture element (pixel) for an image. Each detector is a planer structure which has both the length and width dimensions larger than the wavelength of the incident radiation such that the detector has a adequate collection area for the incident radiation.
A principal limitation in the use of conventional infrared imagers has been the requirement that the imaging device be enclosed within a very cold chamber. The cooling for such devices has most often been provided by the evaporation of liquid gases, such as nitrogen. However, the storage, piping and handling of coolants such as liquid nitrogen has proven to be difficult, time consuming and expensive.
In view of the need for thermal imaging and the difficulties involved in supplying the cooling for the imagers, there exists a need for an infrared radiation detecting device which can function and produce useful signals at ambient temperature.